AbstractIn order to understand the effects of contact shape and sliding direction on tangential coefficient a VTR (Video Tape Recorder) computer system has been developed to visualise the micro‐slip distribution at the contact interface, during the process of micro displacement, before macro sliding.It is shown that micro‐slip distribution is strongly affected by the shape of the contact area and the sliding direction, which gives a good explanation of the observed relationships between tangential coefficient (defined as tangential force divided by normal load) and tangential displacement.It is suggested, as a result, that the VTR‐computer system developed in this study allows useful observation and understanding of the micro‐mechanism of initiation of macro